The running properties of a tire, in particular a pneumatic tire, are greatly dependent on the rubber composition of the tread, and particularly stringent requirements are therefore placed upon the composition of the tread mixture. A great many different attempts have therefore been made to achieve favorable effects on the properties of the tire by varying the polymer components and the fillers in the tread mixture. A factor which has to be taken into account here is that an improvement in one of the properties of a tire is often attended by impairment of another property. Among the interdependent properties where improvement in one property is usually attended by impairment of at least one other property is the trio of abrasion, rolling resistance, and wet adhesion.
U.S. Pat. No. 6,136,943 has already disclosed a method for improving the abrasion performance and the wet adhesion of a pneumatic tire, where the rubber mixture for the tread comprises from 50 to 90 phr of a rubber with glass transition temperature Tg of from −110 to −80° C., from 10 to 50 phr of a rubber with glass transition temperature Tg of from −79 to +20° C., and from 15 to 50 phr of a resin selected from the group consisting of hydrocarbon resins, phenol/acetylene resins, colophony-derived resins, and mixtures of these.
U.S. Pat. No. 7,084,228 B2 discloses the use of resins in the tread mixture in combination with from 40 to 100 phr of a diene elastomer with glass transition temperature Tg of from −65 to −10° C., and from 0 to 60 phr of a diene elastomer with glass transition temperature Tg of from −110 to −80° C., for improving the abrasion performance of pneumatic tires.
Again, United States patent application publication 2004/0092644 and United States patent application publication 2004/0122157 have already disclosed the combination of specific resins with rubbers with low glass transition temperatures Tg in tire tread mixtures for reducing abrasion in pneumatic tires.
The abovementioned citations use polybutadiene as diene elastomer with glass transition temperature Tg of from −110 to −80° C. The citations do not disclose specific functionalized rubber types.